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What Is Modified Atmosphere Packaging (MAP)? [Examples Included]

If you're a food manufacturer, you already know the challenges of keeping that food fresh until it finally gets to the customer. Making sure that the packaging you use is an excellent way to get started, and fortunately, there are numerous ways to find the best packaging materials so that the food doesn't go rancid or spoil along the way.


Modified atmosphere packaging, or MAP, is a process that extends the shelf life of all sorts of fresh food products. It involves substituting the atmospheric air inside a package with a protective gas mix instead. The gas contained in the package does a great job of helping the product stay fresh much longer than it otherwise would.


Why it's So Important


One of the first things that you learn when you're a food manufacturing company is that different food products have different gas and oxygen compositions, depending on the type of food. For instance, red meat needs a lot of oxygen to maintain the correct color, while bread needs low oxygen to avoid mold and mildew. Finally, vegetables often require a three-gas mixture to stay fresh. Knowing foods' gas and oxygen content is also more straightforward than you think.


Ideally, food manufacturers perform shelf-life studies before putting their products on the market and work with gas suppliers to determine what type of gas mixture is appropriate for their particular product. And the amount of gas in the packaging not only helps the food stay fresher for longer, but it also helps the food look good long enough for the customer to decide to buy it while in the store. Food always looks and smells better with the proper packaging and lasts longer.


Without the proper packaging, milk turns sour much sooner, bread gets moldy, and meat can develop a brown color and an unpleasant smell. Several things can cause different foods to spoil. For instance, oxygen can cause oxidation, a type of decay. Fats and oils can oxidize as well and make food go bad. Microbes such as yeast, bacteria, and mold are all around us, and they also grow on food products to make them inedible and dangerous. 


What Can You Do?


Because it is practically inevitable for food to spoil eventually without some intervention, food manufacturers need to know some of those interventions. Essentially, there are several ways to slow down the processes that make food spoil look good and taste good for much longer. Some of those processes are simple and basic, including refrigeration, curing with salt, pickling, and even adding artificial preservatives to the foods to slow down the decaying process.


These methods, however, usually don't last for long and only keep the foods fresh for a limited time. MAP packaging examples that last a lot longer include sealing the food in a package containing the right mixture of natural gasses in the right proportions so that the process of decay slows down even further. You can slow down the decaying process of food by modifying its packaging, and there are two methods of doing that.


The type and proportion of gas you use on the food product is determined by the kind of food in the packaging and the type of change the food experiences. When you know these two things, it's easier to find the proper packaging for that particular product. And it usually starts with removing all of the air out of the packaging and replacing it with a gas or a combination of many different gasses before sealing it tightly so that no unwanted gas or air surrounds the product.


Now, let's take a look at some examples of modified atmosphere packaging, or MAP.


1. Gas Flushing

Gas flush and vacuum

A prevalent MAP technology, gas flushing, is used mainly for food and beverage products. There are three main reasons for gas flushing, and they are:


● It acts as a filter to maintain package conformity

● It displaces oxygen so that oxidation is delayed

● It decreases the growth of aerobic spoiling organisms


During this process, gas -- often nitrogen -- is pumped into the bag, and then the bag is sealed so that ambient oxygen is displaced. This process, in turn, decreases the amount of oxygen found inside the package, which naturally slows down the spoilage rate. The image above shows gas being vacuumed from a container after the flushing process.


2. Packaging with One-Way Valves

Vacuum Bag w/One way valve

Companies sometimes add one-way valves to the exterior of the packaging to allow certain gasses to escape but not let any outside gasses get inside the package. Sometimes, these valves allow air and gases to escape from the container to help better preserve the products inside. Whole coffee beans are often packaged in barrier bags with a one-way valve allowing gases and aroma to escape during storage.  


Carbon monoxide and carbon dioxide are released from the bean during the roasting process. After the beans cool, they continue to release both gases. The vented bags with a one-way valve are perfect for coffee and other consumables releasing gases during storage for premium taste, ventilation, and compact storage.


3. Desiccant Packs

Desiccant Packs

In pill bottles, this MAP technology is often called scavenger packs. Small sachet-type packets usually contain a mixture of iron powder or ascorbic acid, and sometimes activated carbon is used. The ingredients absorb ambient moisture and oxygen, which removes them from the inside of the packaging. Because they continually absorb this extra moisture, they do a great job keeping the product inside the packaging a lot fresher.


4. Barrier Packaging Films

White Barrier Bags

Barrier packaging films are layers of materials also called co-extruded. The type of materials used in the co-extrusion process determines the barrier provided. An oxygen transmission rate measures the barrier protection a bag has. The OTR gauges the amount of oxygen transmitted through the barrier film over a set amount of time. Standard plastic/poly bags have high oxygen transmission rates, co-extruded poly/nylon bags have a much lower transmission rate better suited for MAP packaging. Foil or co-extruded foil bags have low oxygen transmission rates for a maximum barrier.


How Does MAP Technology Protect Foods?


As a general rule, MAP technologies keep foods fresh longer because they decrease their exposure to oxygen. Oxygen can lead to oxidation, and oxidation causes spoilage, discoloration, and even flavors and textures that are a bit "off." They decrease or somehow control the amount of oxygen found in the package, extending the foods' shelf life, keeping the package itself attractive to customers, and keeping the foods fresher much longer.

You may have even noticed that modified atmosphere packaging has become more common during the COVID outbreak of 2020. Many food manufacturers initiated the technology because of the virus, while many others have had a process in place. Today's food packagers and food producers have seen increases in the demand for food products that use MAP technologies, and it's not likely to stop any time soon.


Some of the companies that use MAP technology for their products include:


●      Coffee roasters - Coffee beans can release carbon dioxide after they are roasted, and coffee companies often use one-way valves to release that carbon dioxide so that the package doesn't burst.

●      Fresh fruit and vegetable companies - Two of the most common MAP technologies used with fruits and vegetables include specific barrier packaging films and nitrogen gas flushes. The latter displaces oxygen inside the package, which decreases the oxidation process.

●      Specialty snack manufacturers - Barrier packaging films are typical among snack food manufacturers, especially natural and preservative-free snacks. These films can be a bit pricey, but they put customers at ease knowing the product is safe to eat.

●      Legal cannabis companies - Many of the well-known cannabis companies use MAP technologies that include flushing out the nitrogen gas to extend the product's shelf life.

● Butchers and Meat Processors - Removing oxygen before freezer storage or cold storage will increase shelf life and reduce freezer burn. Vacuum packaging can help double frozen storage times. 


The Advantages of MAP Technology


Modified atmosphere packaging offers numerous advantages for the average food-manufacturing company. These include:

● Preserve food nutrients

● Retain original food flavors

● Eliminate chemical additives/preservatives

● Extend shelf life

● Improve the visual appeal of packaged products

● Protect delicate products (chip bags)




Begin with figuring the length of storage time desired. Those storage times and the way a product is stored will determine the best packaging process to be used. From there, you can decide the optimal machine and materials to accomplish the intended packaging goals.


It is not just the increased freshness and shelf life; it's also the ability to reduce food waste and maximize resources. If you're new to the food manufacturing world, it will behoove you to learn more about MAP and why it is vital to your business. The good news is that U.S. Packaging & Wrapping can help you get started any time you're ready.




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